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The 2016 red tide crisis in southern Chile: Possible influence of the mass oceanic dumping of dead salmons
2020
Armijo, Julien | Oerder, Vera | Auger, Pierre-Amaël | Bravo Lizana, Angela | Molina, Ernesto
In 2016, a massive harmful algal bloom (HAB) of Alexandrium catenella around Chiloe island caused one of the major socio-ecological crisis in Chilean history. This red tide occurred in two distinct pulses, the second, most anomalous, bursting with extreme toxicity on the Pacific coast, weeks after the highly controversial dumping off Chiloe of 4,700 t of rotting salmons, killed by a previous HAB of Pseudochattonella verruculosa. We study the transport of this pollution, analyzing the physical oceanographic conditions during and after the dumping. We find that a cyclonic gyre was present between the dumping site and the coast, visible in satellite altimetry and sea surface temperature data. Using Lagrangian simulations, we confirm that near-surface currents could have brought part of the pollution to the coast, and fueled the bloom. This scenario explains also the anomalous later finding of ammonium near Chiloe. Finally we discuss the mismanagement of risk throughout the events. | Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 3150587
Afficher plus [+] Moins [-]First measurement of human exposure to current use pesticides (CUPs) in the atmosphere of central Chile: The case study of Mauco cohort
2020
Cortés, Sandra | Pozo, Karla | Llanos, Yasna | Martínez, Natalia | Foerster, Claudia | Leiva, Cinthya | Ustáriz, Javier | Přibylová, Petra | Klánová, Jana | Jorquera, Héctor
Chile is a leading agricultural producer and thus consumer of insecticides, herbicides, and fungicides. In Molina, Central Chile, a prospective cohort has been established for studying the incidence and risk factors of chronic diseases in the adult population. Our goals were to measure airborne current use pesticides (CUPs), assess their spatial distribution and potential sources, and estimate health risks for the population in Molina. CUPs were measured using passive air samplers (PAS), deployed on six sites from October 2015 to August 2016. Thirty-eight pesticides were analyzed using high performance liquid chromatography (HPLC), but only nine of them were detected. Chlorpyrifos (CPF) was detected with air concentrations ranging from 444 to 14 624 (pg m(-3)). Diazinon, atrazine, dimethoate, metolachlor, simazine, terbuthylazine and tebuconazole were also detected; only pendimethalin had concentrations as high as those of CPF, with a maximum of 14 927 (pg m(-3)). Backward wind trajectories were used to estimate locations of potential sources contributing to airborne CUPs concentrations. Most of the exposure to CUPs was associated with local sources, while regional sources southern/eastern/western of Molina appear to contribute as secondary sources (soil evaporation followed by atmospheric transport) in spring and summer seasons. A health risk assessment using US-EPA's methodology was carried out for inhalation exposure of detected pesticides. None of the measured CUPs were associated with a hazard quotient (HQ) greater than 1, indicating no significant risk due to inhalation of pesticides in Molina's population with the exception of the group of children below 12 years old. However, further investigations are needed to evaluate others CUPs exposure route such as food consumption and dermal exposure to improve our health risk estimations. | Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) 15130011-15110020 180078 1161673 Vicerrectoria de Investigacion, Pontificia Universidad Catolica de Chile 9/2014 RECETOX Research Infrastructure LM2015051 CZ.02.1.01/0.0/0.0/16_013/0001761
Afficher plus [+] Moins [-]Monitoring the occurrence of microplastic ingestion in otariids along the peruvian and chilean coasts
2020
Pérez Venegas, Diego J. | Toro Valdivieso, Constanza | Ayala, Félix | Brito, Beatriz | Iturra, Lunna | Arriagada, Maite | Seguel, Mauricio | Barrios, Carmen | Sepúlveda, Maritza | Oliva, Doris | Cárdenas Alayza, Susana | Urbina, Mauricio A. | Jorquera, Alberto | Castro Nallar, Eduardo | Galbán Malagón, Cristóbal
Repeated reports of microplastic pollution in the marine pinniped diet have emerged in the last years. However, only few studies address the drivers of microplastics presence and the potential implications for monitoring microplastic pollution in the ocean. This study monitored their in the scats (N = 205) of four pinniped species/subspecies at five different locations in the southern Pacific Ocean (Peru and Chile). Samples from all rookeries contained microplastics, and overall, 68% of the examined scats contained fragments/fibers, mostly blue colored. We confirmed that 81.5% of the fragments/fibers were anthropogenic in origin , but only 30% were polymers. Scats from Juan Fernandez Archipelago presented higher microplastic concentrations than continental rookeries. Also, the common diet in each location may influence the levels found in the samples. This study presents a useful non-invasive technique to track plastic pollution in top predator diets as bioindicators for future surveillance/management plans applied to different location. | Rufford Foundation: N 18815-1. Dirección de Investigación y Doctorados, Universidad Andres Bello. Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), CONICYT FONDECYT: 11150548, 116504, 111609059. Instituto Antártico Chileno Grant: INACh RT_12_17. Conicyt PCI: REDI 170292, REDI 170403. Ministerio de Economia, Fomento y Turismo through Iniciativa Científica Milenio (Núcleo Milenio INVASAL). Direccion de Investigación Universidad de Variarais: DIUV 38/2013. Morris Animal Foundation fellowship: N D16ZO-413. Saint Louis Zoo. Chicago Zoological Society. Kansas City Zoo. Woodland Park Zoo.
Afficher plus [+] Moins [-]Field Monitoring of 2010-Tsunami Impact on Agricultural Soils and Irrigation Waters: Central Chile
2016
Casanova Pinto, Manuel | Salazar Guerrero, Osvaldo | Oyarzún, Irene | Tapia Fernández, Yasna | Fajardo, Mario
An in situ post tsunami study was conducted to assess the effect of water management and rainfalls in soil properties and water quality at a low-lying coastal area of central Chile affected by Mw8.8 Earthquake Tsunami the night of 27 February 2010. Soil samples were taken at two depths (0 to 20 and 20 to 40 cm) during 2010 and late 2012. Water quality in a local shallow well was also monitored in 2010 and 2012. High soil salinity was recorded 2 months later than tsunami occurs, closely associated to water-soluble chloride and cations (Cl- >> Na+ >> Ca2+> Mg2+> K+), ionic toxicities, and vegetal inhibition (Vasconcellea pubescens) by less available water to plants. An initial reduction in soil pH due to ionic strength and coarse-textured class of soil was observed and the sodium adsorption ratio (SAR) in soil varied between 5.7 and 11.2 (mmol L-1)(0.5) showing to be saline. Although SARw values are very high (> 18 (mmol L-1) 0.5), it does not exist risks of reduction on soil infiltration rates according to ECw (> 5 dS m(-1)) obtained. After 2 years, soil salinity was drastically reduced in the affected areas due to high soil permeability and natural attenuation (rainfalls and leaching effects), with sulfate and bicarbonate concentrations showing excessive values. Further, irrigation water quality returned to pre-tsunami situation, with only levels of sodium slightly exceeding desirable range from health point of view. Finally, it is suggested a proper design of irrigation systems before implementing other management practices
Afficher plus [+] Moins [-]Assessment of nitrogen and phosphorus pathways at the profile of over-fertilised alluvial soils. Implications for best management practices
2018
Salazar, Osvaldo | Fuentes, Ignacio | Seguel Seguel, Oscar | Nájera de Ferrari, Francisco | Casanova, M.
Contrasting soil profiles (coarse-textured and fine-textured) treated with brilliant blue (BB) dye tracer, inorganic nitrogen (N) and phosphorus (P) concentrations along and between stained preferential flow pathways were examined for an irrigated and overfertilised maize monoculture system at the Mediterranean central Chile. The PO4-P concentrations were 2- to 10-fold higher in areas with BB than in areas without BB below 0.5-m soil depth in both soils. This elevated concentration was attributed to transport through cracks in fine-textured soil and finger flow in coarse-textured soil. The highest PO4-P value (13 mg kg(-1)) was found in areas with BB at the fine-textured soil. There were no significant differences in inorganic N concentration between areas with and without BB for both soils, which suggest that the effects of preferential flow are less important for inorganic N forms. There was a strong significant (p < 0.01) positive correlation between PO4-P and NH4-N concentrations in the fine-textured soil, and the amounts retained were clearly proportional to the clay content. Strategies for reducing N and P losses must be placed on good agronomic management of irrigated maize cropping system including accurate calculation of N and P fertiliser rates and establishment of suitable mitigation measures such as cover cropping. | FONDECYT 1150572
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